Statement of the Technical Field
The invention relates generally to Electronic Article Surveillance (“EAS”) systems, and more particularly to improvements in EAS tag detection performance.
Description of the Related Art
EAS systems use EAS transmitters to excite markers or tags which are present in a detection zone. The transmitter periodically generates a burst of electromagnetic energy at a particular frequency to excite the EAS tag. When a marker tag is excited in the detection zone during the time of the burst, the marker tag will generate an electromagnetic signal which can usually be detected by a receiver. One type of EAS system utilizes acousto-magnetic (AM) markers. The general operation of an AM type EAS system is described in U.S. Pat. Nos. 4,510,489 and 4,510,490. As is known, the transmitter or exciter in many common AM type EAS systems will transmit bursts or pulses of electromagnetic energy at 58 kHz and then listen for a response from an EAS tag that is present in a detection zone.